Ecosystem

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Transcript of Ecosystem

AP - ES EcosystemEcologyStudy of relationships of organisms with one another and their environment:

Organisms: a SINGLE member of a species.Species: organisms capable of interbreeding and producing fertile offspring.Population: organisms of the SAME species interacting within a community.Community: composed of DIFFERENT species interacting with one another. Ecosystem: a biological community and it’s physical environment (biotic & abiotic)Biosphere: all ecosystems on the entire Earth.

Clumped: some areas are dense with organisms while others contain few. Occurs when resources are patchy. Most common form of dispersion.Examples: Elephants clumped together near watering hole.Example: Lions clumped together in prides.Example: Red-headed Woodpecker have specific requirements.Random: random spacing patterns / little interaction between members of the population.usually occurs in habitats where env. conditions and resources are consistent.characterized by lack of strong social interactions.Example: Dandelion seeds being dispersed by windUniform: Uniform spacing between individuals. Need to maximize space between individuals arises from competition, territory, etc.Example: Penguins defending nest sites.Example: Fiddler crabs defending their burrows

Specialist species (r) live in narrow niches and are sensitive to environmental changes – therefore, more prone to extinction. Example: giant panda, Senegal Chameleon

When environmental conditions are stable, specialists have advantage since they’re well adapted to specific niche (competitive exclusion principle)

When habitats change, generalists fare better since more adaptable to change.

Law of Tolerance and Limiting FactorsLaw of Tolerance: the existence, abundance and distribution of species depends on the tolerance level to biotic and abiotic factors. Ex) climate, topography, biological factors

Law of Minimum: organisms will survive until they run out of resources (food) is exhausted.

Limiting FactorsLimiting Factor: any factor (biotic or abiotic) that limits or prevents the growth of a population. Ex) soil nutrients, available water or light, temperature, pH, DO, salinity, predation, disease, shortage of mates, etc

Resource PartitioningResources are limitedSome species evolved to share a resource

Temporal partitioning: two species use same resource at DIFFERENT TIMES.e.g. monkeys feed on fruit during day while fruit bats feed at night.

Spatial partitioning: competing species use same resource by occupying DIFFERENT AREAS of habitat.e.g. flounders feed along benthos while pelagic fishes feed in open waters.

Morphological partitioning: species use same resource but have evolved DIFFERENT STRUCTURES to use resource.e.g. two different species of bees evolved different proboscis lengths to access different types of flower nectar.Interactions Among SpeciesInteractions among species can benefit, harm, or not affect one of the species involved.

Amensalism: one species suffers and the other is not impacted: ex) bread mold, Penicillium secretes penicillin, which kills competing bacteria.

Commensalism: one species benefits and the other is not impacted. ex) juvenile bar jack fishes swing along side of large barracuda to avoid medium sized predators.

Mutualism: BOTH species benefit.ex) flower and pollinating honey bee.

Parasitism: one species benefits and the other is harmed. ex) lamprey and lake trout.

Competition: two species compete for a resource.Intraspecific competition: two members of the SAME species compete.Interspecific competition: two different species compete.Keystone SpeciesKeystone Species: a species whose presence contributes to a diversity of life and whose extinction would lead to the extinction of other forms of life.

Keystone species have disproportionate impact on how ecosystems function.

ex) sea star prey on sea urchins, mussels, etc. that have no other predators. Removal of sea star, would lead to overpopulating of prey species which decimate coral reef.

ex) sea otters prey on sea urchins. If sea otters were removed, urchins would destroy kelp forests, which support vast amounts of other species.Indicator SpeciesIndicator Species: a species whose presence, absence, or well-being indicates the health of its ecosystem as a whole. Provide EARLY WARNING system! (Canary in Coal Mine)

Trophic CascadingTrophic Cascade: occurs when the food web is disrupted by the removal of a top predator or producer, which then has a ripple down or up affect on the rest of the ecosystem. ex) removal of wolves from Yellowstone had subsequent influence on coyote, elk, ravens, bear, and willow. Cascading can be "bottom up" or "top down".Aquatic OrganismsWater:provides buoyancyreduces need for support structureshigh heat capacity translates into less temperature regulation expenditure for organismallows dispersal of gametes / larvae to new areasfilters UV radiationorganisms adapted: tough shells, exoskeletons, salt removal mechanisms, low metabolic rates (due to cooler ambient temperatures)Desert OrganismsDesert plants adaptions:spaced apart due to limiting factors.primarily consist of succulents (cacti) and short lived annuals (wildflowers)Succulent adaptations:small surface areaopen stomata at nightwaxy coating to minimize transpirationdeep roots to tap groundwatersharp spines for protectionsecrete toxins into soil to discourage competition (allelopathy)

Desert animal adaptation:smaller surface arealive undergroundnocturnalsecrete concentrated urineinsects & reptiles have thick shells / skin to reduce water lossGrassland OrganismsAdaptations:Grasses grow from the bottom (basal meristem) so they can recovery from grazing.Drought resistantDeciduous trees & shrubs shed leaves during dry season to conserve waterHerbivores eat vegetation at different heights so as not to competeSome organisms migrate to find water while others go dormantOrganisms burrow to avoid predationCamouflage plays a big role in evading predators / ambushing preyForest OrganismsTropics:some organisms live in canopies where shelter and food are abundantepiphytes (orchids and bromeliads) live on tree branches & have access to falling organic matter. Obtain moisture from air rather than soilplants in understory have large leaves to maximize sunlight absorption.plants and trees have shallow roots to capture nutrients in soilFlowers have elaborate devices to attract pollinators since wind in minimal

Temperate Deciduous Forests:broad-leaf deciduous trees lose their leaves in winter and become dormantshift metabolism from photosynthesis in summer to utilizing glucose and amino acids in winter (also keeps trees from freezing and acts as natural antifreeze)

The water temperature is near freezing, and there is no light in this zone.

Very few creatures can be found in these freezing, dark, and bone crushing (high pressure) depths.

Most inhabitants are invertebrates - animals without a backbone, such as basket stars and tiny squids.

Those organisms that do exist in this zone rely on bioluminescence. (Video)

Coastal ZonesEstuariesBays or semi-enclosed bodies of brackish water that form where rivers enter the ocean.Contain a high amount of plant life.Usually carry rich sediments (nutrients ) from the river.

Wetlands perform several important environmental functions.Act like filters or sponges that absorb and remove sediment & pollutants from the water. Control flooding by absorbing extra water when rivers overflow.Provide a home for large amount of biodiversity.

NPP is calculated by taking the Gross Primary Productivity (GPP), which is the TOTAL amount of sugar the plants produce via photosynthesis, and subtracting it from the amount of energy plants need for growth, maintenance, repair, and reproduction.

GPP - Respiration = NPP

NPP measured in kilocalories per square meter per year (kcal / m2 / y)Chemotrophs: bacteria that convert inorganic compounds into glucose. Considered to be producers but use NO light. Primary producers within hydrothermal vent communities.Chemotrophic bacteria play a role within the terrestrial nitrogen cycle too.ChemosynthesisFood ChainsFood Chains: linearrepresented as series of stepsarrows depict flow of energy outwardmay indicate biomass (dry weight of organism(s))overly simplistic; not representative of entire community's trophic progressionEnergy TransferTen Percent Rule:only 10% energy transferred between trophic levels90% lost via:respirationdigestionevading predatorsprimary consumers obtain more energy than secondary and so onenergy measured in kilocalories (kcal)BiomagnificationAside from food, toxins can also travel through food chainsConcentration of toxins increase at each successive levelMany toxins cannot be broken down by organismsToxins accumulate in fatty tissueBioaccumulation: term used to describe toxin buildup in tissue of living organism.Biomagnification: term used to describe increasing concentration of these toxins as they travel THROUGH the food chain.Food WebsMore accurate method of depicting trophic activity

the number of organisms the environment can support.Carrying CapacityBiotic Potential: the potential growth of a population assuming no limiting factors existed.Environmental Resistance: factors (drought, starvation, available mates) that restrict the biotic potential of a populationDesertWetlandLakeGrasslandSavannaTaigaTemperate Deciduous ForestTemperate Rain ForestChaparralTropical Rain ForestTundraBiome DistributionBiodiversityBiodiversity: means the diversity, or variety, of plants and animals and other living things in a particular area or region.

Species Richness: the number (variety) of different species represented in an ecological community.

Species Evenness: how close in NUMBER each species in an environment are to one another. (how proportionate)Natural SelectionNatural Selection: process whereby organisms better adapted to their environment tend to survive and produce more offspring.

allows organisms to evolveworks on individual leveladvantageous traits are passed on to offspringoccurs over successive generationsenvironmental change triggers natural selectionArtificial SelectionThe selective breeding of organisms by humans for specific characteristics.

Types of EvolutionCo-evolutionStabilizing, Direction & Diversifying SelectionDivergent EvolutionConvergent EvolutionParallel EvolutionAdaptive RadiationPhylogenetic TreeAlso known as a “tree of life”.Organisms are grouped and classified based on three characteristics:Physical characteristicsDNA similaritiesBehavioral characteristics Mating rituals, territorial, aggression, etc.The more of these characteristics two organisms have in common, the more closely related they are according to evolution.SuccessionThe gradual transition from one community to another following a disturbancePrimary Succession: the colonization of an area with bare groundPioneer Species: those species such as lichen and mosses that do not require soil and are first to colonize an area.Climax Community: the community best able to exploit the available resources (the final community)Secondary Succession: occurs where a community previously existed.